Protocol

Limits

ankor.sh bounds what each node sends, because a node may be run by someone else. Your controller can apply the same limits or its own. It enforces either with the answers in Limiting a node.

ankor.sh’s limits

The numbers are constants in the contract, most of them in limits.ts. An agent within them is never limited. Ankor’s agent stays within them even with 64 busy slots.

• A node has at most 64 slots. Its hello lists at most the 50 newest demos. Each demo’s file name has at most 160 characters.
• A socket message is at most 960 KiB. A socket carries one hello, which is due within 10 seconds of the upgrade.
• Each kind of message draws on a budget per connection. The budget allows a burst and refills at a steady rate. Where the table says “a slot”, add that amount for every slot the node has. The slot count comes from the node’s last hello or applied set_config reply. Before the first of these, count one slot.

Messages	Burst	Refill	Over budget
Every message, in bytes	32 MiB + 1 MiB a slot	512 KiB/s + 16 KiB/s a slot	close
hello, slot_status, node_status, server_exited, demo, demo_removed, event_backlog, shutdown, unreadable	64 + 32 a slot	2/s + 1/s a slot	close
log_batch, log_index	128, and 16 MiB	32/s, and 256 KiB/s	dropped
resource_batch	10	1/s	dropped
cs2_update_progress	50	10/s	dropped
demo_progress	10	2/s	dropped
phase_change, score, backup	0 + 16 a slot	1 every Infinity s + 1/s a slot	dropped
reply to no open request	32	1/s	close
WebSocket pings	5	1/s	close

• A log replay that would exceed the byte budget arrives without its oldest lines, so frequent replays do not close the socket.
• ankor.sh closes a socket that breaks these rules with the code and reason that Closing the socket lists. After a close for a larger message or a budget, ankor.sh answers the node’s upgrades with 429 for a minute.
• More than 10 upgrades of one node within a minute are answered 429 until that window ends.
• More than 20 missing or unknown tokens from one address within a minute are answered 429 until that window ends. An IPv6 address counts as its whole /64.
• Event uploads may carry 32 MiB + 4 MiB a slot in a minute. Each request counts 1 KiB more than its body. Past that budget, ankor.sh answers 429.
• The agent handles at most one check_cs2_build in a minute and drops any that comes sooner. The agent’s scheduled read of the public CS2 build, every 30 minutes, is not limited.
• ankor.sh’s demo receiver accepts one upload per node at a time. It answers 429 to a second upload. It answers 403 to an upload that would push the node’s stored demos past the service’s quota.

Limiting a node

Enforce limits with the answers below. The agent needs nothing else from you. It backs off, retries and sends a fresh hello by itself. It keeps every event it stored.

• Socket over a budget: close it with code 1008 and rate_limited. Refuse the node’s upgrades with 429 for as long as you want to keep the node out. The agent redials with its usual backoff. Its next hello carries its state.
• A message you would rather drop: ignore it and keep the socket open. Only the messages that the table marks dropped are safe to ignore. The others carry state that the agent sends again only after it reconnects.
• Event upload: answer 429. The agent keeps the batch and retries with backoff.
• Demo upload: answer 429. The agent keeps the file and retries. Answers has the details.
• The agent ignores Retry-After and the response body of a 429.